X0306 4 2018-02-20 0 0001610682 USD Partners LP USDP 0001621019 USD GROUP LLC 811 MAIN STREET, SUITE 2800 HOUSTON TX 77002 1 0 1 0 0001621021 US DEVELOPMENT GROUP, LLC 811 MAIN STREET, SUITE 2800 HOUSTON TX 77002 1 0 1 0 0001621293 USD HOLDINGS LLC 811 MAIN STREET, SUITE 2800 HOUSTON TX 77002 1 0 1 0 0001707921 ECP ControlCo, LLC 51 JOHN F. KENNEDY PARKWAY, SUITE 200 SHORT HILLS NJ 07078 1 0 1 0 0001621292 ENERGY CAPITAL PARTNERS III, LLC 51 JOHN F. KENNEDY PARKWAY, SUITE 200 SHORT HILLS NJ 07078 1 0 1 0 0001697506 Energy Capital Partners GP III, LP 51 JOHN F. KENNEDY PARKWAY, SUITE 200 SHORT HILLS NJ 07078 1 0 1 0 0001594547 ENERGY CAPITAL PARTNERS III-A, LP 51 JOHN F. KENNEDY PARKWAY, SUITE 200 SHORT HILLS NJ 07078 1 0 1 0 0001621385 ENERGY CAPITAL PARTNERS III-B (USD IP), LP 51 JOHN F. KENNEDY PARKWAY, SUITE 200 SHORT HILLS NJ 07078 1 0 1 0 0001621413 ENERGY CAPITAL PARTNERS III-C (USD IP), LP 51 JOHN F. KENNEDY PARKWAY, SUITE 200 SHORT HILLS NJ 07078 1 0 1 0 COMMON UNITS (LIMITED PARTNER INTERESTS) 2018-02-20 4 C 0 2092709 0 A 7371672 I See Footnotes SUBORDINATED UNITS (LIMITED PARTNER INTERESTS) 2018-02-20 4 C 0 2092709 0 D COMMON UNITS 2092709.0 4185418 I See Footnotes Effective February 20, 2018, pursuant to the terms for the third subordinated unit tranche as set forth in the Issuer's second amended and restated agreement of limited partnership, 2,092,709 subordinated units representing limited partnership interests in the Issuer held by USD Group LLC ("USD Group") converted on a one-for-one basis into common units representing limited partnership interests in the Issuer. US Development Group, LLC ("USD") is the parent company of USD Group LLC ("USD Group") which is the sole owner of the membership interests of USD Partners GP LLC, the Issuer's general partner. USD manages USD Group. ECP ControlCo, LLC ("ECP ControlCo") is the managing member of Energy Capital Partners III, LLC ("ECP"), which is the general partner of Energy Capital Partners GP III, LP ("ECP GP"), which is the general partner of each of Energy Capital Partners III-A, LP ("ECP-A"), Energy Capital Partners III-B (USD IP), LP ("ECP-B"), and Energy Capital Partners III-C (USD IP), LP ("ECP-C") and together with ECP-A and ECP-B, the "ECP Funds"). As a result, ECP ControlCo, ECP and ECP GP have voting and investment control over the securities owned by the ECP Funds. USD Holdings, LLC ("USD Holdings") and the ECP Funds are members of USD and, with ECP and ECP ControlCo, may be deemed to indirectly beneficially own the limited partnership interests beneficially owned by USD. Following the transactions reported herein, USD Group directly holds 7,371,672 common units and 4,185,418 subordinated units representing 33.8% of the common units and 100% of the subordinated units for a combined 44.3% of the limited partnership interests in the Issuer. USD Holdings is a 45.5% member of USD, and may therefore be deemed to indirectly beneficially own 3,354,111 common units and 1,904,365 subordinated units, representing 45.5% of the limited partnership interests held by USD Group. ECP ControlCo, ECP, ECP GP and the ECP Funds collectively hold 49.2% of the membership interest in USD, and may therefore be deemed to indirectly beneficially own 3.626,863 common units and 2,059,226 subordinated units, representing 49.2% of the limited partnership interests held by USD Group. Subordinated units will convert into common units on a one-for-one basis in separate sequential tranches. Each tranche will be comprised of 20.0% of the subordinated units outstanding as of October 15, 2014. A separate tranche will convert on each business day occurring on or after October 1, 2015 (but no more than once in any twelve-month period) subject to certain conditions being met. /s/Adam Altsuler, Chief Financial Officer, USD Group LLC 2018-02-22 /s/ Adam Altsuler, Chief Financial Officer, US Development Group, LLC 2018-02-22 USD Holdings LLC; By: /s/ Michael R: Curry, Manager 2018-02-22 ECP ControlCo, LLC By: /s/ Peter Labbat, Managing Member 2018-02-22 Energy Capital Partners III, LLC By: ECP ControlCo, LLC, its managing member By: /s/ Peter Labbat, Managing Member 2018-02-22 Energy Capital Partners GP III, LP By: Energy Capital Partners III, LLC, its general partner By: ECP ControlCo, LLC, its managing member By: /s/ Peter Labbat, Managing Member 2018-02-22 Energy Capital Partners III-A, LP By: Energy Capital Partners GP III, LP, its general partner By: Energy Capital Partners III, LLC, its general partner By: ECP ControlCo, LLC, its managing member By: /s/ Peter Labbat, Managing Member 2018-02-22 Energy Capital Partners III-B (USD IP), LP By: Energy Capital Partners GP III, LP, its general partner By: Energy Capital Partners III, LLC, its general partner By: ECP ControlCo, LLC, its managing member By: /s/ Peter Labbat, Managing Member 2018-02-22 Energy Capital Partners III-C (USD IP), LP By: Energy Capital Partners GP III, LP, its general partner By: Energy Capital Partners III, LLC, its general partner By: ECP ControlCo, LLC, its managing member By: /s/ Peter Labbat, Managing Member 2018-02-22